318 horsepower

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i think the carb is too much....unless you already have it. for a 318 i would go with a demonsizzler prepped TQ.

there is a member on here running his 360 on with a 650 Holley and he will be in the 12s this summer....he actually went slower with a 750 i loaned him.

i would think a repro 340 cam would be the ticket until you get more compression. a good timing set from Cloyes or etc...MAKE SURE YOU DEGREE YOUR CAM.

sb
 
I think that's a wise choice. But..There's always a but...Leave the small intake valves in the 302s. Increase the exh to 1.60, and port the exh side, with minore cleanup on the intake side. It will run better that way...Also, the guides will need to be trimmed slightly, and the cam needs to be chosen carefully because the pistons have no valve reliefs.
 
I'll add to what moper has stated, that the exh will flow 185-190 without porting, but doing a 75* cut and a good valve job should give you more than the 318 will ever need. Also I strongly agree with the stock size valves on the intake side, do a back cut and a good valve job and trim the guide a bunch, gasket match the intake side to the 360 port window and you'll be in the 225-230 range on cfm's. This is what I did and the car has done a best of 7.303 @ 98 mph 1/8 with a 1.53 60 ft time. Also this was useing a 280 hyd. comp cams cam and a stock short block with all the good machining done.
 
One more thing...dont forget to have the top seal area of the guides trimmed too...stock guides dont leave a lot of room for lift.
 
So I have found a casting number that I cannot identify and am looking for some help to get specifics on the block. 4587530-3182 anyone able to direct me or pass along any info.
 
My bad.............
I jsut got to the block to clean up the number and it is actually 4387530-31828 but I still do not see it in my MP book for casting numbers.
 
Porting heads, without a flow bench to compare your apples to each other, is pointless. There was an article in one of the car mags a few years back that gave detailed instructions on how to build a simple flow bench for doing porting work. I will try to see if I can find the article and post up what mag it was in, so anyone who want's to know can find it and build one for themselves, then you will be able to TRULY port a set of heads, anything less and you might just as well be throwin money in the fireplace. IMO.
 
Though I am late on this discussion I will input a little bit. Aren't 318's pretty solid performers for the street with some basic mods? I was always told by some pretty old Mopar guys that back in the day 318's were good little hotrod engines. You can beat them up to no end and they keep on going.
 
Short stroke means quick high winding....Long stroke gives bottom end torque...Whoever said drag racing does not need torque is(not meaning in the wrong way) wrong...Torque is what moves the car... That is why the 360 works better stock. (Longer Stroke) + more cubic inches. Short stroke means HP or high winding, but less torque...Which causes greater chance of breakage...This is why the 440 is fast and low maintenance.(Long stroke + Low rpm)...Why would you take a high winder and put a small runner or less flow head on it...Why would you spend 100's of dollars on buying valves, porting, & springs when you can go to salvage, buy stock set of 360 heads and do a $110.00 valve job and flow better if you are on a budget and flow is what you will need with a high winder(stock 360 head...1.88 intake). Always advance your cam in a sb at least 4*(will bring power range to lower rpm) unless you use hughes cam, because this is built into a hughes cam. Why does the stroke motor run faster? Because of more cubic inches?...To some degree, but the reason is for the longer stroke(more torque) to move the car quicker...If your car is geared and tired right, if you p/u a 10th of a second in the first 60' of the race track, you will pick up close to three 10th over the whole 1/4 mi. So, does this mean the quicker 60' the better et?..Yes! 318's are great. I run one with stock bottom end (3.910 bore), stock 340 cam(advanced 8 degrees), Pair of stock 360 J heads, LD340 intake, and I believe it was the 650 carter carb, w/ 1 5/8 headers and run 13.70's in a 3000 lb car...It was great when a buddy of mine was only running 13.40's w/ a 360... I am in the process of building a 349 cu in out of a 318 and a 390 out of a 318...We will see what the 318 can do...LOL...Lee
 
70dartman said:
Short stroke means quick high winding....Long stroke gives bottom end torque...Whoever said drag racing does not need torque is(not meaning in the wrong way) wrong...Torque is what moves the car... That is why the 360 works better stock. (Longer Stroke) + more cubic inches. Short stroke means HP or high winding, but less torque...Which causes greater chance of breakage...This is why the 440 is fast and low maintenance.(Long stroke + Low rpm)...Why would you take a high winder and put a small runner or less flow head on it...Why would you spend 100's of dollars on buying valves, porting, & springs when you can go to salvage, buy stock set of 360 heads and do a $110.00 valve job and flow better if you are on a budget and flow is what you will need with a high winder(stock 360 head...1.88 intake). Always advance your cam in a sb at least 4*(will bring power range to lower rpm) unless you use hughes cam, because this is built into a hughes cam. Why does the stroke motor run faster? Because of more cubic inches?...To some degree, but the reason is for the longer stroke(more torque) to move the car quicker...If your car is geared and tired right, if you p/u a 10th of a second in the first 60' of the race track, you will pick up close to three 10th over the whole 1/4 mi. So, does this mean the quicker 60' the better et?..Yes! 318's are great. I run one with stock bottom end (3.910 bore), stock 340 cam(advanced 8 degrees), Pair of stock 360 J heads, LD340 intake, and I believe it was the 650 carter carb, w/ 1 5/8 headers and run 13.70's in a 3000 lb car...It was great when a buddy of mine was only running 13.40's w/ a 360... I am in the process of building a 349 cu in out of a 318 and a 390 out of a 318...We will see what the 318 can do...LOL...Lee
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Not to be a jerk, but why did Mopar use the 340 for racing if it has a short stroke and large bore? I was told torque moves the car but horsepower wins the races.
 
408Dartman said:
Not to be a jerk, but why did Mopar use the 340 for racing if it has a short stroke and large bore? I was told torque moves the car but horsepower wins the races.
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"horsepower Sells cars, torque wins races" is how it is quoted i believe. i say, put a high winder to be different and slam a 5k stall converter on the tranny and 4.10's out back! now you've solved the 60' time issue. set-up your valve-train to handle the 8k plus shift points.. :tongue9:
 
408Dartman said:
Not to be a jerk, but why did Mopar use the 340 for racing if it has a short stroke and large bore? I was told torque moves the car but horsepower wins the races.
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yep true to a point, but you need a big enough bore to stuff larger valves without shrouding them right? I had a 8k+ rpm 273 back in the day, much rather have the torque of the new 416 stroker. You can keep the thing more dependable and not have to rev the heck out of it to make it fly. Takes less gearing etc.

It is a balancing act of both, but more T is the key. It is the torque that gives you the pulling power.

points all well taken to guys! my 2.5 cents.. :thumbup:
 
408Dartman said:
Not to be a jerk, but why did Mopar use the 340 for racing if it has a short stroke and large bore? I was told torque moves the car but horsepower wins the races.
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Didn't take you as being a jerk...Everyone has two cents...That is what this is all about...But the 340 will not run unlees you cam it to rev high...My last motor was a 345 (30 over 340). Had to leave the starting line at 8200 rpm because there is not enough stroke(torque) to move the car at 4000rpm...(Stick shift)...Don't get me wrong, the 340 will fly, but you better get into your pocket book because you will constantly be breaking things when you rev one high...The whole concept of this conversation was the gentleman is on a budget...I love the sound of a high winder, but lets face it...It is not for a guy that is on a budget !....Long Stroke, Low RPM, & decent heads is for a guy on a budget, because this creates Low Maintenance and a guy on a budget cannot afford to be working on one every week just to make the next race !....Lee :wav:
 
Some Food For Thought !

408 cu. in. ...1 hp per cu. in....408 hp (4" stroke)(torque Monster)

360 cu. in. ...1.13 hp per cu. in.408 hp (3.580 Stroke)(medium Torque)

340 cu. in. ...1.20 hp per cu. in 408 hp (3.310 Stroke)(no torque)

318 cu in. ...1.28 hp per cu. in. 408 hp (3.310 Stroke)(no torque)

Which is most economical to run and easiest to achieve ?....Lee
 
70dartman said:
Didn't take you as being a jerk...Everyone has two cents...That is what this is all about...But the 340 will not run unlees you cam it to rev high...My last motor was a 345 (30 over 340). Had to leave the starting line at 8200 rpm because there is not enough stroke(torque) to move the car at 4000rpm...(Stick shift)...Don't get me wrong, the 340 will fly, but you better get into your pocket book because you will constantly be breaking things when you rev one high...The whole concept of this conversation was the gentleman is on a budget...I love the sound of a high winder, but lets face it...It is not for a guy that is on a budget !....Long Stroke, Low RPM, & decent heads is for a guy on a budget, because this creates Low Maintenance and a guy on a budget cannot afford to be working on one every week just to make the next race !....Lee :wav:
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Good point :thumbup:
 
ProStreetDuster said:
Anyone know off hand how much the compression would be raised on a 8.5 to 1 318 if the stock heads were swapped out for 302s?
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Depending on where you start from, maybe .75 pt. Less on earlier models with smaller open chambers.
 
Since I was the one that originally started this thread I figure that since I have been quiet reading the masses and learning a whole lot I should ask a similar question as I still cannot find anything in writting any where to answer that same question about mine. My 318 is a 1987 and came with the 302 heads. What should my compression be at, besides LOW ???? Am I in the 8:1 range?
 
If you take the heads off, cc them, and then figure it...I'd wager you are right on the edge of 8.3ish. Higher (slightly) than mid 70s..lower than you want to be.
 
and by CCing them you mean putting the piston all the way up and measuring the distance of the space between the flat edge of the block and the top of the piston correct? or am I still not understanding what I need to do here?
 
Ah. Ok. there are several number syou need to get to calculate the compression ratio. If you dont know your piston specs for dish volume or valve relief volume these need to be measured for the calculators to work. For a set of heads, things like factory tolerances in castings and machining, valve jobs done in the past, maybe an engine rebuild, or valve replacement, or even sunk valves all combine to change the volume of the chambers. This is measured with a large burette or syringe, an alcohol based fluid, a small amount fo grease, and a flat plate of glass or lexan/ plexiglass about 1/4" thick with a countersunk hole in the center. You spread the grease around the circumference of the chamber, on the head gasket mating surface. You then place the plexi with the counterunk side up on the head, with the hole lined up near the top edge of the chamber. You can see if the grease is sealing all the way around by looking at the plexi. Air bubles mean leaks when fluid's in there. Then you fill the burrette or syringe with fluid (I use isopropyl alcohol w/windshield washer fluid to make it blue) and slowly release the fluid into the hole in the plexi, going slow to let the fluid displace the air completely. When it's full, and no air is int here, record how much fluid you unsed to fill it. That is that chamber's "CC figure". You basically do the same for the piston, but I like to use the 1" down method. you coat the bore lightly (piston down in the bore) with grease about 1.25" down from the deck surface. Then using a dial indicator (or ruler if you have to) bring the piston up until there is 1" of space between the deck surface and the top edge of the piston. (the flat just above the rings...not the center of a dish or dome). DO not move the piston in any direction but up, and if you go past 1" down, you have to go back and start from scratch with fresh grease. When the piston is 1" down, run a ring of grease around the top of the bore, again, hole in the plate near the highest side edge of bore (depends on what the shortblock is on/in). Then, fill and record how much fluid it took. That takes into account every nook and cranny, the shape of the valve head, the depth of the seats, the milling, the dome, valve releifs or dish shapes, the dead space over the rings..you name it. Then, when you're figuring the compression, you will need to modify the formula for the 1" downfill.
 
Had a 318 running mid 11's in a 74 Duster. Was kinda radical, Ported X heads, pop up pistons, roller cam...........

I'm not sure in the real world if you could get a set of 302 heads to run low 12's, unless the car is REAL light, hooks up perfectly, and is driven flawless.
 
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